In order to increase the downforce or for better road adhesion and overall for improving the road holding quality and for optimum stabilization of the vehicle, air deflector devices are mounted on motor vehicles, in particular on sports vehicles, which air deflector devices can be brought either merely from a non-use position into a use position, but also, under some circumstances, can be brought into a multiplicity of different use positions. The adjustment is customarily performed via an electric motor, preferably a direct current electric motor which is activatable by means of a control device depending on the respectively required settings of the air deflector device. The adjustment of the air deflector device is brought about via a step-down or step-up mechanism connected downstream of said electric motor and via means for mechanically transmitting the actuating force, which is applied by the electric motor, to the air deflector device. The technical requirements imposed on such an actuating drive in modern motor vehicles are relatively high: a relatively simple and highly compact construction which is not prone to faults and has an extremely low weight is required and at the same time an operation which is as quiet or as noise-free as possible is intended to be possible.
A series of solutions are disclosed in the prior art, with which it is attempted to resolve the problems which arise. Thus, DE 103 48 284 A1 discloses an actuating drive for an air deflector device, in particular for a rear spoiler of a vehicle, which actuating drive brings about the adjustment of the rear spoiler with a step-down mechanism, which is driven by the electric motor, via a spindle drive. DE 10 2008 024 893 A1 has disclosed a solution in which the drive device for the air deflector device is intended to be arranged in a manner decoupled from the body of the motor vehicle via a separate mounting element in order to be able to minimize noise.
WO 2008/041757 A1 has disclosed an actuating drive device, in which an air deflector device is intended to be extended or retracted via a centrally arranged step-up mechanism, which is driven by the electric motor, and an adjustment shaft, which is driven by said step-up mechanism, via racks which interact with gearwheels on the adjustment shaft.
DE 37 11 386 A1 and U.S. Pat. No. 4,925,236 disclose actuating drives for air deflector devices, in which the electric motor brings about the adjustment of the air deflector device via a worm and a worm wheel and partially via further gear elements. These solutions are clearly based on the finding that high to very high stepping-down can be achieved with worm drives and that worm drives belong to the gear devices having the least production of noise. In addition, worm drives are generally self-locking.
DE 43 23 938 shows and describes an air deflector device, which is combined with a rear view mirror device, for a vehicle. In this system, two worm/worm wheel drives are combined in order to be able to ensure the synchronization of the movements of air deflector device and rear view mirror device.